What is the effect when fans are mounted in series?

When fans are mounted in series, the primary effect achieved is an increase in pressure. In this configuration, each fan contributes to the overall pressure increase by adding its own pressure rise to that of the other fans. This is particularly useful in applications where greater resistance to airflow is encountered, such as in long duct systems or when overcoming significant static pressures.

In series arrangements, while the volumetric flow rate remains the same as that produced by a single fan, the cumulative pressure created by the multiple fans allows for more effective movement of air against obstacles. This characteristic makes series fan configurations ideal for achieving higher pressures needed for specific tasks or environment control.

The other options reflect outcomes that do not occur with series fan setups: flow remains unchanged in terms of volume, and a negative pressure would not be generated unless a specific design causes it.